DNS Question

I have a quick question about using alternative DNS servers?

Is it good to have two?

Comodo configured my computer’s DNS to use their servers… while my router is configured to use OpenDNS. I am not experiencing any problems and infact, my internet is faster than ever.

Is this a good thing or bad thing? Should I remove one or not?

How is Windows set regarding to DNS servers? Use the servers as given by the gateway (Open DNS in your case) or did you manually set to use Comodo servers? You are using one of them depending on your settings. You are not using two at the same time.

What DNS servers you use boils down to to two important factors imo: speed and what extra services you appreciate from DNS servers.